Jeffrey T Petty

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Prepared within biocompatible poly(amidoamine) dendrimer hosts, blue emitting Au8 nanodots were prepared with fluorescence quantum yields more than 100 times larger than any previously prepared. The strong size-dependent blue emission from these from monodisperse Au8 nanodots was measured to be 41% in aqueous solution and 52% in methanol. These easily(More)
A bifunctional oligonucleotide integrates in situ synthesis of a fluorogenic silver cluster with recognition of a target DNA sequence. With the template C(3)AC(3)AC(3)GC(3)A, a complex forms with 10 silver atoms that possesses electronic transitions in the near-infrared and that is detected at nanomolar concentrations using diode laser excitation. Pendant(More)
DNA encapsulates silver clusters, and these hybrid nanomaterials form molecular sensors. We discuss a silver cluster-oligonucleotide sensor with four characteristics. First, a specific reporting cluster forms within a single-stranded DNA. This template uses the 5' cluster domain CCCCAACTCCTT with different 3' recognition sites for complementary(More)
Photostability, inherent fluorescence brightness, and optical modulation of fluorescence are key attributes distinguishing silver nanoclusters as fluorophores. DNA plays a central role both by protecting the clusters in aqueous environments and by directing their formation. Herein, we characterize a new near infrared-emitting cluster with excitation and(More)
The reduction of silver cations bound to the oligonucleotide dC(12) was used to form silver nanoclusters. Mass spectra show that the oligonucleotides have 2-7 silver atoms that form multiple species, as evident from the number of transitions in the fluorescence and absorption spectra. The variations in the concentrations of the nanoclusters with time are(More)
We analyzed seasonal water samples from the Cheat and Tygart Valley river basins, West Virginia, USA, in an attempt to classify streams based on water chemistry in this coal-mining region. We also examined temporal variability among water samples. Principal component analysis identified two important dimensions of variation in water chemistry. This(More)
NanoCluster Beacons (NCBs), which use few-atom DNA-templated silver clusters as reporters, are a type of activatable molecular probes that are low-cost and easy to prepare. While NCBs provide a high fluorescence enhancement ratio upon activation, their activation colors are currently limited. Here we report a simple method to design NCBs with complementary(More)
The high affinity of Ag+ for DNA bases has enabled creation of short oligonucleotide-encapsulated Ag nanoclusters without formation of large nanoparticles. Time-dependent formation of cluster sizes ranging from Ag1 to Ag4/oligonucleotide were observed with strong, characteristic electronic transitions between 400 and 600 nm. The slow nanocluster formation(More)
Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based(More)
The interaction between DNA and a benzothiazole-quinoline cyanine dye with a trimethine bridge (TO-PRO-3) results in the formation of three noncovalent complexes. Unbound TO-PRO-3 has an absorption maximum (lambda(max)) of 632 nm, while the bound dyes (with calf thymus DNA) have electronic transitions with lambda(max) = 514 nm (complex I), 584 nm (complex(More)